KR102318011B1 - Method and apparatus for low power operation of terminal and base station in mobile communication system - Google Patents

Abstract

The present disclosure relates to a communication technique that converges a 5G communication system for supporting a higher data rate after a 4G system with IoT technology, and a system thereof. The present disclosure provides intelligent services (eg, smart home, smart building, smart city, smart car or connected car, healthcare, digital education, retail business, security and safety related services, etc.) based on 5G communication technology and IoT-related technology. ) can be applied to

Description

Method and apparatus for low-power operation of a terminal and a base station in a mobile communication system

The present invention relates to a communication system, and more particularly, to a method and apparatus for reducing a control burden and power consumption of a network and saving power consumption of a terminal.

Efforts are being made to develop an improved 5G communication system or pre-5G communication system in order to meet the increasing demand for wireless data traffic after the commercialization of the 4G communication system. For this reason, the 5G communication system or the pre-5G communication system is called a 4G network after (Beyond 4G Network) communication system or an LTE system after (Post LTE) system.

In order to achieve a high data rate, the 5G communication system is being considered for implementation in a very high frequency (mmWave) band (eg, such as a 60 gigabyte (60 GHz) band). In order to mitigate the path loss of radio waves and increase the propagation distance of radio waves in the ultra-high frequency band, in the 5G communication system, beamforming, massive MIMO, and Full Dimensional MIMO (FD-MIMO) are used. ), array antenna, analog beam-forming, and large scale antenna technologies are being discussed.

In addition, for network improvement of the system, in the 5G communication system, an evolved small cell, an advanced small cell, a cloud radio access network (cloud RAN), and an ultra-dense network (ultra-dense network) , Device to Device communication (D2D), wireless backhaul, moving network, cooperative communication, Coordinated Multi-Points (CoMP), and interference cancellation Technology development is underway.

In addition, in the 5G system, FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), which are advanced coding modulation (ACM) methods, and FBMC (Filter Bank Multi Carrier), which are advanced access technologies, NOMA (non-orthogonal multiple access), and sparse code multiple access (SCMA) are being developed.

On the other hand, the Internet is evolving from a human-centered connection network where humans create and consume information to an Internet of Things (IoT) network that exchanges and processes information between distributed components such as objects. Internet of Everything (IoE) technology, which combines big data processing technology through connection with cloud servers, etc. with IoT technology, is also emerging. In order to implement IoT, technology elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. , M2M), and MTC (Machine Type Communication) are being studied. In the IoT environment, an intelligent IT (Internet Technology) service that collects and analyzes data generated from connected objects and creates new values in human life can be provided. IoT is the field of smart home, smart building, smart city, smart car or connected car, smart grid, health care, smart home appliance, advanced medical service, etc. can be applied to

Accordingly, various attempts are being made to apply the 5G communication system to the IoT network. For example, in technologies such as sensor network, machine to machine (M2M), and machine type communication (MTC), 5G communication technology is implemented by techniques such as beam forming, MIMO, and array antenna. there will be The application of a cloud radio access network (cloud RAN) as the big data processing technology described above is an example of the convergence of 5G technology and IoT technology.

On the other hand, the RRC (Radio Resource Control) state for the wireless communication terminal to transmit and receive data is conservatively designed according to the previous generation communication system centered on voice calls. For example, since the terminal maintains a waiting time such as in an RRC connected state (eg, Connected DRX) even when there is no traffic arrival for a certain period of time after receiving traffic, power consumption due to this is serious. In addition, in the case of smartphone users, keep alive messages that are not related to user QoS (quality of service) are frequently generated as data. have.

When dual connectivity, which operates macro cells and small cells in the same/similar frequency band environment in the sub 6GHz band, is applied to 5G as it is, inefficiency problems in terms of power consumption are further increased. will appear large. Through the Dual Connectivity technology, the UE performs communication with the macro cell and the small cell by continuously performing measurement on the macro cell and the small cell and activating a plurality of modems in the RRC connected state. This may be a problem in which the power consumption of the terminal is aggravated when considering the power consumption in the mmWave beamforming environment of the high frequency band.

Therefore, in order to solve the above problem, an object of the present invention is to extend the RRC idle period and increase the terminal power efficiency by minimizing the RRC connected state for the 5G cell through the CP tail minimization control of the base station.

In addition, another object of the present invention is to minimize the 5G cell link activation state (RRC Connected state and measurement performance) of the terminal, but also satisfy the user's QoS (particularly, latency criteria). In addition, even if the RRC Idle state is entered early due to CP tail shortening, a network signaling overhead (N/W Signaling overhead) and terminal power consumption caused by frequent transition from the RRC Idle state to the RRC Connected state additionally occur minimized It also serves another purpose.

In order to solve the above problems, a method of a terminal supporting a first RAT (Radio Access Technology) and a second RAT in a mobile communication system includes a second method by a second RAT through a first connection by a first RAT. detecting that a condition for activating a connection is satisfied; and when transmission and reception of traffic through the second connection is completed and a timer set for the second connection expires, releasing the second connection; The timer for the connection is set differently from the timer for the first connection.

According to an embodiment of the present invention, the condition for activating the second connection is determined based on the buffer amount of data to be transmitted and received by the terminal, and the timer for the second connection may be set shorter than the timer for the first connection. have.

According to an embodiment of the present invention, the method further includes the step of performing a measurement on the second connection before the step of detecting, and the measurement is to determine whether the UE exists within coverage of the second connection and the second connection. It may be performed based on at least one of information on a service to be provided through the service and information on traffic to be transmitted/received through the second connection.

According to an embodiment of the present invention, before the sensing step, the method may further include the step of confirming that the terminal enters within the coverage of the second connection using an indicator received through the first connection.

In order to solve the above problems, a terminal supporting a first RAT (Radio Access Technology) and a second RAT in a mobile communication system may transmit and receive a signal through a first connection by a transceiver and a first RAT. and a control unit configured to detect that a condition for activating the second connection by the RAT is satisfied, and to release the second connection when transmission and reception of traffic through the second connection is completed and a timer set for the second connection expires, , the timer for the second connection is set differently from the timer for the first connection.

According to an embodiment of the present invention, the condition for activating the second connection is determined based on the buffer amount of data to be transmitted and received by the terminal, and the timer for the second connection may be set shorter than the timer for the first connection. have.

According to an embodiment of the present invention, the control unit is configured to perform measurement on the second connection before the sensing process, and the measurement is provided through the second connection, whether the terminal exists within the coverage of the second connection or not. It may be performed based on at least one of information on a service to be transmitted and information on traffic to be transmitted/received through the second connection.

According to an embodiment of the present invention, the control unit may be configured to confirm that the terminal enters within the coverage of the second connection using an indicator received through the first connection before the sensing step.

In order to solve the above problems, in a method of a base station for communicating with a terminal supporting a first RAT (Radio Access Technology) and a second RAT in a mobile communication system, the terminal uses a first connection through the first RAT. 2 When it is detected that the condition for activating the second connection by the RAT is satisfied, the step of activating the second connection with the terminal and transmission/reception of traffic through the second connection are completed, and a timer set for the second connection is activated. upon expiration, releasing the second connection, wherein the timer for the second connection is set differently from the timer for the first connection.

According to an embodiment of the present invention, the condition for activating the second connection is determined based on the buffer amount of data to be transmitted and received to the terminal, and the timer for the second connection may be set shorter than the timer for the first connection. have.

According to an embodiment of the present invention, before the terminal detects that the condition is satisfied, the terminal performs measurement on the second connection, and the measurement is, whether the terminal exists within the coverage of the second connection, It may be performed based on at least one of information on a service to be provided through the second connection and information on traffic to be transmitted/received through the second connection.

According to an embodiment of the present invention, before the terminal detects that the condition is satisfied, the terminal may check that the terminal enters within the coverage of the second connection using an indicator received through the first connection.

In order to solve the above problems, a base station communicating with a terminal supporting a first RAT (Radio Access Technology) and a second RAT in a mobile communication system includes a transceiver for transmitting and receiving a signal and a terminal using the first RAT. If it is detected that the condition for activating the second connection by the second RAT is satisfied through the first connection, the second connection with the terminal is activated, the transmission/reception of traffic through the second connection is completed, and the second connection is established for the second connection. and a controller configured to release the second connection when the timer expires, wherein the timer for the second connection is set differently from the timer for the first connection.

According to an embodiment of the present invention, the condition for activating the second connection is determined based on the buffer amount of data to be transmitted and received to the terminal, and the timer for the second connection may be set shorter than the timer for the first connection. have.

According to an embodiment of the present invention, before the terminal detects that the condition is satisfied, the terminal performs measurement on the second connection, and the measurement is, whether the terminal exists within the coverage of the second connection, and the second connection. This may be performed based on at least one of information on a service to be provided through the second connection and information on traffic to be transmitted/received through the second connection.

According to an embodiment of the present invention, before the terminal detects that the condition is satisfied, the terminal may check that the terminal enters within the coverage of the second connection using an indicator received through the first connection.

Through the present invention, since the 5G cell RRC connected state is kept to a minimum through the CP tail minimization control operation of the base station for terminals supporting 5G Multi-RAT, a power consumption saving effect of the terminal is expected. In addition, cost efficiency effect is expected through reduction of power consumption of 5G base station (RU/TRxP) by restricting measurement operation for 5G cell of the terminal, and furthermore, radio resource use efficiency through reduction of peripheral interference between 5G cells increase is expected.

1 is a diagram schematically illustrating a Scell Addition/Release operation method according to dual connectivity of a communication system.
2 is a diagram illustrating an example of a small cell measurement configuration and a terminal/base station operation according to dual connectivity (eg, 3GPP Release 12) of a communication system, an operation in which the terminal continuously performs Macrocell and small cell measurement, and RRC It is a diagram showing the operation process of the terminal and the macrocell and small cell base station in the connected state.
3 is a control plane (Control plane: CP) and user plane (User plane: UP) between the core network structure and the terminal-base station in the LTE-5G Tight Integration (NSA, Non-Standalone) operating environment according to an embodiment of the present invention. ) is a diagram showing an example of the connection state.
4 is a diagram illustrating an example of a connection state between base stations and signaling between protocol layers in an LTE-5G Tight Integration (NSA) operating environment according to an embodiment of the present invention.
5 is an RRC connection management method for low power of a terminal according to an embodiment of the present invention, and is a state diagram for multi-RAT (4G, 5G) low power operation in an LTE-5G Tight Integration (NSA) operating environment. ) is a diagram explaining the
6 is an RRC connection management method for low power of a terminal according to an embodiment of the present invention, and terminal modem for each state according to an operation scenario for multi-RAT (4G, 5G) low power operation in an LTE-5G Tight Integration operating environment It is a diagram explaining the operation process.
7 is an RRC connection management method for low power of a terminal according to an embodiment of the present invention, and a control signal flow for multi-RAT (4G, 5G) low power operation in an LTE-5G Tight Integration operating environment and a base station / It is a diagram explaining the operation process of the terminal modem.
8 is a control plane (Control plane: CP) and a user plane (User plane: UP) between the core network and the base station in an LTE-5G Independent environment (Multi-Link: ML or SA: Standalone) according to an embodiment of the present invention. It is a diagram showing an example of a connection state.
9 is a diagram illustrating an example of a connection state between base stations and signaling between protocol layers in an LTE-5G independent environment (Multi-Link: ML) according to an embodiment of the present invention.
10 is a diagram illustrating a state diagram for multi-RAT (4G, 5G) low-power operation in an LTE-5G independent operating environment according to an embodiment of the present invention.
11 is a view for explaining a terminal modem operation process for each state according to an operation scenario for multi-RAT (4G, 5G) low-power operation in an LTE-5G independent operation environment according to an embodiment of the present invention.
12 is a view for explaining a control signal flow and a base station/terminal modem operation process for multi-RAT (4G, 5G) low-power operation in an LTE-5G independent operating environment according to an embodiment of the present invention.
13 is a diagram illustrating an example of implementing a terminal connection latency reduction operation based on a traffic end point (TCP flag FIN) for an efficient 5G Radio Tail (User Inactivity timer) period shortening operation according to an embodiment of the present invention; It is a diagram illustrating the FIN (final) indication of the TCP packet from the transmitting end and the receiving end and ACK transmission to confirm it.
14 is a diagram illustrating another example of implementing a terminal connection latency reduction operation based on a traffic end point (TCP flag FIN) for an efficient 5G Radio Tail (User Inactivity timer) period reduction operation according to an embodiment of the present invention; As such, it is a diagram including a FIN indicating the end of transmission as a type of flag indicated in the TCP header.
15 is a diagram illustrating another example of implementing a terminal connection latency reduction operation based on a traffic end point (TCP flag FIN) for an efficient 5G Radio Tail (User Inactivity timer) period shortening operation according to an embodiment of the present invention; As such, it is a diagram showing the hierarchical structure and unit in the wireless communication protocol.
16 is a diagram illustrating an example of a DL Traffic generation-based operation as a server operation according to a terminal request (UL) for a control operation to minimize a 5G CP tail section according to an embodiment of the present invention.
17 is a server operation based on the cost of a process in which the UE transitions from the RRC Idle state to the RRC Connected state for the 5G CP Tail section minimization control operation according to an embodiment of the present invention, illustrating an example of a DL Traffic generation-based operation. It is a drawing.
18 is a diagram illustrating the structure of a terminal according to an embodiment of the present invention.
19 is a diagram illustrating the structure of a base station according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. At this time, it should be noted that in the accompanying drawings, the same components are denoted by the same reference numerals as much as possible. In addition, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted.

In describing embodiments in the present specification, descriptions of technical contents that are well known in the technical field to which the present invention pertains and are not directly related to the present invention will be omitted. This is to more clearly convey the gist of the present invention without obscuring the gist of the present invention by omitting unnecessary description.

For the same reason, some components are exaggerated, omitted, or schematically illustrated in the accompanying drawings. In addition, the size of each component does not fully reflect the actual size. In each figure, the same or corresponding elements are assigned the same reference numerals.

Advantages and features of the present invention, and a method for achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains. It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

At this time, it will be understood that each block of the flowchart diagrams and combinations of the flowchart diagrams may be performed by computer program instructions. These computer program instructions may be embodied in a processor of a general purpose computer, special purpose computer, or other programmable data processing equipment, such that the instructions performed by the processor of the computer or other programmable data processing equipment are not described in the flowchart block(s). It creates a means to perform functions. These computer program instructions may also be stored in a computer-usable or computer-readable memory that may direct a computer or other programmable data processing equipment to implement a function in a particular manner, and thus the computer-usable or computer-readable memory. It is also possible that the instructions stored in the flow chart block(s) produce an article of manufacture containing instruction means for performing the function described in the flowchart block(s). The computer program instructions may also be mounted on a computer or other programmable data processing equipment, such that a series of operational steps are performed on the computer or other programmable data processing equipment to create a computer-executed process to create a computer or other programmable data processing equipment. It is also possible that instructions for performing the processing equipment provide steps for performing the functions described in the flowchart block(s).

Additionally, each block may represent a module, segment, or portion of code that includes one or more executable instructions for executing specified logical function(s). It should also be noted that in some alternative implementations it is also possible for the functions recited in blocks to occur out of order. For example, two blocks shown one after another may in fact be performed substantially simultaneously, or it is possible that the blocks are sometimes performed in the reverse order according to the corresponding function.

At this time, the term '~ unit' used in this embodiment means software or hardware components such as FPGA or ASIC, and '~ unit' performs certain roles. However, '-part' is not limited to software or hardware. The '~ unit' may be configured to reside on an addressable storage medium or may be configured to refresh one or more processors. Thus, as an example, '~' denotes components such as software components, object-oriented software components, class components, and task components, and processes, functions, properties, and procedures. , subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. The functions provided in the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. In addition, components and '~ units' may be implemented to play one or more CPUs in a device or secure multimedia card.

The present invention provides an operation of a base station and a terminal for achieving Energy Efficiency KPI, which is being discussed in the 3rd Generation Partnership Project (3GPP) Radio Access Network (RAN) 5G (5th generation) communication system standardization process, and an apparatus accordingly suggest The standard defines energy-efficient operation with the main goal of improving the power efficiency [bit/J] of terminals and base station networks by more than 1000 times within the next 10 years. To this end, in order to solve the possibility of additional power consumption due to the beamforming transmission method, which is essential when operating mmWave in a high frequency band, a control method for reducing the active operation time of the terminal is being discussed.

In the present invention, 5G network structure candidate LTE-5G Tight Integration environment (NSA: Non-stand Alone environment) and ML (Multi Link) based LTE-5G Independent environment (SA: Stand Alone environment) RRC connection control and maintenance method Suggests about In particular, when beamforming transmission is performed in the mmWave band, which is a high frequency band, a control process for minimizing the CP tail (radio tail or user inactivity timer), which is the remaining duration of the RRC Connected state of the base station, is proposed. do. Accordingly, in order to minimize battery power consumption of networks and terminals operating through multi-RAT modems (LTE and 5G), we propose a method of supporting the function of maintaining the 5G cell RRC connected state to a minimum.

The RRC state for the wireless communication terminal to transmit and receive data was designed conservatively according to the design of the previous generation focusing on voice calls. For example, since the terminal maintains the waiting time in the RRC connected state (eg, Connected DRX) even though there is no traffic arrival for a certain period of time after receiving the traffic, power consumption due to this is serious. In addition, in the case of smartphone users, keep alive messages, etc., which are not related to the user's quality of service (QoS), are frequently generated as data.

Through the present invention, 5G Multi-RAT terminals are expected to save power consumption of the terminal because the 5G cell RRC connected state is kept to a minimum through the CP tail minimization control of the base station. In addition, we propose a method of increasing radio resource usage efficiency by reducing power consumption of 5G base stations (RU/TRxP) and reducing ambient interference between 5G cells by restricting the 5G cell measurement operation of the terminal.

Radio Access Technology (RAT), which is named 5G in the description below, is a new RAT to support high-capacity traffic, and has a high link capacity among RATs supported by Multi-RAT Capable terminals. It means a RAT that can support higher QoS, such as low latency or low latency. On the other hand, legacy RAT refers to a RAT that can support relatively low QoS among RATs supported by Multi-RAT Capable UEs, but consumes less power and is advantageous in terms of energy efficiency.

In addition, 5G RAT can be understood as a high-frequency base station due to the characteristics of the frequency band occupied. At this time, the legacy RAT, 4G LTE, can be understood as a low-frequency base station because it occupies a relatively low frequency band. On the other hand, even in the communication system according to the 5G RAT, the sub-6 GHz band and the above-6 GHz band are functionally separated to serve the roles of the above-described low-frequency base station and high-frequency base station.

According to another embodiment, the following inventions can also be applied to a communication system operating with a 4G cell as a master node (Master Node, MN) and an NR mmWave cell as a secondary node (SN), and sub-6 GHz (Low Frequency, LF) It can also be applied to a communication system that operates by using the base station as the master node (MN) and the above-6GHz (High Frequency, HF) base station as the secondary node (SN).

First, FIG. 1 is a diagram schematically illustrating a Scell Addition/Release operation method according to dual connectivity of a communication system. According to the operation of Dual Connectivity (eg, described in 3GPP Release 12 Small cell Enhancement), the macro cell base station controls the RRC connection of the small cell through the RRC message to add/release the connection with the small cell (Addition/Release). ), and based on this, the Scell Link Connection of the terminal is controlled. A paging operation for notifying whether data arrives in the RRC Idle state of the UE also operates through the macrocell link.

2 is a diagram illustrating an example of a small cell measurement configuration and terminal/base station operation according to dual connectivity (eg, 3GPP Release 12) of a communication system. In FIG. 2 , the terminal continuously performs measurement on the macrocell and the small cell, and operates with the macrocell and the small cell base station in the RRC connected state.

When the small cell measurement configuration for Dual Connectivity (eg, described in 3GPP Release 12) is completed through the RRC reset message (S210), the UE/base station performs measurement and measurement for the small cell (MR: Measurement Report) Processes (S220, S230) are performed (S270). Subsequently, the UE activates the Scell modem based on an Addition message for the small cell (RRC Message, S240) from the macro cell base station and operates as (RRC_Connected) (S280). In particular, the UE continuously performs Scell measurement even before Scell Addition, and the UE deactivates the Scell modem based on a Release message (RRC message, S260) for the small cell from the macrocell base station. This Dual Connectivity technology requires the UE to continuously measure macro cells and small cells, and in the RRC connected state, the UE activates multiple modems (performs macrocell and small cell operations), which intensifies power consumption of the UE. there was a problem with

Considering the power consumption in the mmWave beamforming environment of the high frequency band, power consumption when the above-described dual connectivity operation (macrocell and small cell link operation in the same/similar frequency band environment in the Sub 6 GHz band) is applied to 5G as it is On the other hand, the problem of inefficiency becomes more pronounced.

Therefore, the present invention solves the above problems, but it is necessary to satisfy the following matters. First, it is an object of the present invention to minimize the 5G cell RRC connected state through the CP tail minimization control of the base station to extend the idle period and increase the terminal power efficiency. In addition, it is necessary to minimize the 5G cell link activation state (RRC_Connected state and measurement operation) of the terminal, but at the same time satisfy the user QoS (latency standard satisfaction). In addition, it is necessary to minimize network signaling overhead (N/W Signaling overhead) and terminal power consumption caused by frequent transition from Idle to Connected state even when entering an early idle state due to CP tail shortening.

3 shows a core network structure and a terminal-base station control plane (Control plane: CP) and a user plane (User plane: UP) in an LTE-5G Tight Integration (NSA, Non-Standalone) operating environment according to an embodiment of the present invention; ) is a diagram showing an example of the connection state. A process of selectively operating the measurement operation for the 5G cell of the terminal as a first operation method for minimizing the 5G link activation state of the terminal according to an embodiment will be described.

When the 5G cell modem of the terminal operates in a high frequency band, a common control signal (eg, synchronization, system information, reference signal, etc.) is transmitted by beamforming transmission. Power consumption is caused in the process of transmitting and receiving. On the other hand, a terminal supporting Multi-RAT (Capable) can transmit and receive low data rate traffic through legacy RAT (4G/3G/2G, etc.) prior to 5G. It is advantageous in terms of power consumption to minimize the activation state of the 5G cell link in the terminal for high data rate traffic transmission. Since the terminal is mostly operated with a waiting time without transmission rather than a transmission progress time for the 5G cell link, such an improved measurement operation is very important for improving the power efficiency of the terminal.

RRC State operation between LTE and 5G connections of a multi-RAT capable terminal can be operated in the following two ways. First, the LTE-5G interworking operation shown in FIGS. 3 to 7 is an operation of a base station and a terminal in a 5G non-standalone (NSA) environment. Second, the LTE-5G independent operation shown in FIGS. 8 to 12 is the operation of the base station and the terminal in a 5G standalone (SA) environment.

3 is a view showing a core network structure and a terminal-base station control plane (Control plane: CP) and a user in an LTE-5G Tight Integration (NSA) operating environment, which is one of 5G network structure candidates in a communication system according to an embodiment of the present invention. It is a diagram showing an example of a plane (User plane: UP) connection state. In the NSA environment shown in FIG. 3, since the LTE base station uses a frequency band of 6 GHz or less, it can operate as a macro cell to provide wider coverage. Since the 5G base station uses a frequency band of 6GHz or higher, including 28GHz and mmWave bands, it can operate as a small cell. At this time, the 4G and 5G core networks exist separately, but there is an interface that connects them. In the case of a 4G (LTE) link, both a control plane (CP) and a user plane (UP) between the terminal and the base station can be connected. On the other hand, in the case of 5G (NR: New Radio), both the control plane (CP) and the user plane (UP) between the terminal and the base station are connected, or the control plane between the terminal and the base station (Control plane: CP) is It is entirely dependent on the LTE base station, and it may be assumed that only the user plane (UP) is performed through 5G connection. As another operation example, in the control plane (CP) between the terminal and the base station, some control functions are implemented in the LTE base station, and the remaining control functions are implemented through the 5G link, and the user plane (UP) is connected to 5G. You can think of the operation of sending and receiving through .

4 is a diagram illustrating an example of a connection state between base stations and signaling between protocol layers in an LTE-5G Tight Integration (NSA) operating environment, which is one of 5G network structure candidates according to an embodiment of the present invention. 4 shows 4G and 5G protocol layers RRC (Radio Resource Control) layer, PDCP (Packet Data Convergence Protocol) layer, RLC (Radio Link Control) layer, MAC (Medium Access Control) layer and PHY (Physical) layer independent of the layer It shows whether to operate as a protocol layer or a merge protocol layer. In 5G, the so-called 'option 2' structure in which the PDCP layer and the RLC layer are implemented separately is being discussed. For example, the 4G and 5G protocol layers operate as independent protocol layers for the RLC, MAC, and PHY layers, while the RRC layer and The PDCP layer may use a merge operation method.

5 is a diagram for explaining a state diagram for multi-RAT (4G, 5G) low power operation in an LTE-5G Tight Integration operation (NSA) environment as an RRC connection management method for low power of a terminal.

In the embodiment shown in FIG. 5, the detailed operation scenario of the terminal is 1) 5G link activation necessity and availability detection operation, 2) 5G modem activation time determination operation, 3) 4G and 5G C-DRX waiting period in RRC Connected state Including the differential setting and application behavior of

First, 1) the UE must perform a preliminary operation (eg, beam scanning or measurement) before activating (turn on) the 5G (NR) high-frequency band modem receiver. According to an embodiment, the criteria for detecting the need to start such a preliminary operation are a) whether the terminal is currently within the coverage of the NR base station, b) service information of the traffic that needs to be transmitted (eg, service type) ) and QoS required by the service, c) at least one of the data capacity of the traffic requiring transmission support and the state of the buffer being accumulated in the terminal/base station (ie, the amount of data accumulated in the buffer) can be selected.

In the above embodiment, the process of performing the above-described preliminary operation (beam scanning and/or measurement) may be set by the 4G base station instead of the 5G base station and performed by the terminal. Specifically, the 4G base station may set a condition for triggering an event for the terminal to perform a preliminary operation, and the terminal may set a preliminary operation (beam scanning and/or measurement) for the 5G base station according to the event set by the 4G base station. is to perform

In the LTE-5G Tight Integration (NSA) environment, since 5G RAT connection can be supported through 4G RAT connection between the terminal and the LTE base station, when the terminal is first connected to the network, the 4G modem is first activated (510). Subsequently, when detecting that the terminal moves and enters within 5G coverage, the terminal performs a 5G discovery operation ( 520 ). At this time, the process of detecting entering into the 5G coverage includes an operation of determining based on an indication provided by a base station (network), for example, on system information broadcast by the 4G base station. A 1 bit 5G indicator can be newly added. Accordingly, the terminal receiving the 5G indicator from the 4G base station can know whether the 5G base station exists within the coverage of the 4G base station, and the terminal starts scanning in the 5G (NR) related frequency band. At this time, since the terminal is before activating (turn on) the 5G (NR) high-frequency band modem receiver, the 5G coverage-related indicator provided by the base station (network) will be transmitted as System Information of the LTE base station. In this case, the 1 bit 5G indicator is information for informing the UE that the 5G small cell exists within the macrocell of the corresponding LTE base station.

Subsequently, in addition to the indication base provided by the base station (network) as described above as a reference for the operation of the terminal to start 5G scanning, the service type of uplink or downlink traffic (eg, high-capacity data service of eMBB (enhanced mobile broadband)) In the case of starting a low-latency URLLC (ultra-reliable low latency communication) service, etc.) can be another criterion. When uplink/downlink traffic of the above-described specific service occurs, the UE may start a preliminary operation (Scanning or measurement) for activating (turn on) the 5G (NR) high-frequency band modem receiver. In addition, a preliminary operation (Scanning or measurement) for activating (turn on) the 5G (NR) high-frequency band modem receiver can be started based on the capacity of uplink or downlink traffic expected by the terminal or base station.

Unlike the 1-bit 5G indicator, when it is determined that a preliminary operation needs to be started according to the service type and capacity of downlink traffic, an indication provided by the base station (network) is required for the base station to notify the terminal, According to an embodiment, the base station may transmit an RRC (re)configuration message to the terminal in a unicast manner. According to another embodiment, the on-demand system information ( It is also possible to transmit on-demand System Information) so that the network instructs the terminal to perform a preliminary operation.

In addition, when it is determined that a preliminary operation needs to be started according to the service type and capacity of uplink traffic, the terminal reports a traffic event to the base station through 4G RAT or low frequency link to inform the base station of this. (traffic event report) is transmitted. According to an embodiment, the base station may transmit an RRC (re)configuration) message to the terminal in a unicast manner based on the traffic event report of the terminal. According to another embodiment, for the base station to notify the terminal that it is necessary to start a preliminary operation (eg, beam scanning and/or measurement) for activating (turn on) the modem receiver of the NR (5G) frequency band A method in which the network instructs the terminal to perform a preliminary operation by transmitting system information, common system information or minimum system information, or on-demand system information or other system information as an operation. possible.

When the terminal recognizes through an indicator transmitted by the 4G base station that it is necessary to start a preliminary operation (Scanning or measurement) for activating (turn on) the 5G (NR) high-frequency band modem receiver according to the above-described process, or When recognizing through RRC (re)configuration or on-demand SI provided by the base station (network), the terminal transmits a response signal to the base station to confirm that it will initiate a preliminary operation to activate the 5G modem. have.

Subsequently, after the 5G discovery process is terminated, the UE determines the 5G modem activation time (determining the 5G ON time) may be performed based on a) a buffer state of each terminal of the base station and b) a buffer state of the terminal. Various layers such as i) PDCP layer, ii) RLC layer, iii) MAC layer, and iv) PHY layer may correspond to the protocol layer that is the reference of the buffer state of the base station and the terminal. For example, when the 5G modem activation time is determined based on the PDCP buffer, the 5G modem of the terminal will be activated according to the PDCP buffer state for each terminal of the base station and/or the PDCP buffer state of the terminal ( 530 ).

More specifically, when the amount of buffer for each terminal of the base station or the buffer amount of the terminal increases to more than the threshold value TH_1, first, the base station performs a preliminary operation (Scanning or measurement) is recognized (520). Afterwards, when the buffer amount for each terminal of the base station or the buffer amount of the terminal increases to more than the second threshold value TH_2 (TH_1 < TH_2), the operation of activating the 5G (NR) high frequency band modem receiver of the terminal is performed (530).

On the other hand, the two operations (preliminary operation and 5G modem activation operation before 5G modem activation) according to the above-described buffer amount may be initiated based on a 5G link activation request signal of a terminal or base station, and such an activation request signal It may operate based on the completion time of reception of the response feedback message corresponding to It may be performed by starting data transmission after a time gap).

According to another embodiment, after the 5G discovery process is terminated, the operation of the terminal determining the 5G modem activation time (5G ON time determination) may be determined based on c) PDCP duplication activation. In more detail, the Master Node (4G macrocell, lower frequency base station) sets whether to activate PDCP Duplication with RRC based on the operation of PDCP Duplication, and dynamically controls whether PDCP Duplication is activated with MAC CE, etc. Based on the 5G modem activation time includes the operation of determining.

Furthermore, after the 5G discovery process is finished, the operation of the terminal determining the 5G modem activation time (determining the 5G ON time) is, ) may be determined based on According to an embodiment, when the mobile speed of the terminal is high and the threshold value (for example, 120 km/h) or more and the handover latency requirement is less than the threshold value (for example, 1 second or 0), it operates only with the MN link and uses the SN It can operate to perform data transmission to the continuously activated SN without activating or deactivating the SN. In addition, it may operate to perform the mobility support of the terminal through the continuously activated MN without deactivating the MN.

Next, among the above-described embodiments, the differential setting and application operation of the C-DRX waiting period of 4G and 5G in the RRC Connected state will be described. The operation for 4G/5G CP Tail differential operation according to an embodiment may include an operation of preferentially switching the 5G Link to a low power mode (C-DRX or Idle DRX) when there is no transmission/reception traffic. For example, if the user-inactivity timer (ie, CP tail) of 5G modem is determined to be 1 second and the user-inactivity timer of 4G modem is set to 10 seconds, after 1 second from the last transmission/reception traffic, the 5G modem operates first. After being deactivated, the 4G modem remains in the C-DRX state, and after 10 seconds, the 4G modem is also deactivated and the terminal transits to the RRC idle state.

Meanwhile, in the RRC layer related standard document 3GPP TS 36.331, parameters related to low power operation are described in Tables 1 to 4 below.

MAC- MainConfig field descriptions drx - Config
Used to configure DRX as specified in TS 36.321 [6]. E-UTRAN configures the values in DRX-Config-v1130 only if the UE indicates support for IDC indication. E-UTRAN configures drx-Config-v1130 only if drx - Config (without suffix) is configured. drx - InactivityTimer
Timer for DRX in TS 36.321 [6]. Value in number of PDCCH sub-frames. Value psf1 corresponds to 1 PDCCH sub-frame, psf2 corresponds to 2 PDCCH sub-frames and so on. drx-RetransmissionTimer
Timer for DRX in TS 36.321 [6]. Value in number of PDCCH sub-frames. Value psf1 corresponds to 1 PDCCH sub-frame, psf2 corresponds to 2 PDCCH sub-frames and so on. In case drx-RetransmissionTimer-v1130 is signaled, the UE shall ignore drx - RetransmissionTimer (ie without suffix). drxShortCycleTimer
Timer for DRX in TS 36.321 [6]. Value in multiples of shortDRX-Cycle. A value of 1 corresponds to shortDRX-Cycle, a value of 2 corresponds to 2 * shortDRX-Cycle and so on.

DRX-Config ::= CHOICE {
release NULL,
setup SEQUENCE {
onDurationTimer ENUMERATED {
psf1, psf2, psf3, psf4, psf5, psf6,
PSF8, PSF10, PSF20, PSF30, PSF40,
psf50, psf60, psf80, psf100,
psf200},
drx-InactivityTimer ENUMERATED {
psf1, psf2, psf3, psf4, psf5, psf6,
PSF8, PSF10, PSF20, PSF30, PSF40,
psf50, psf60, psf80, psf100,
PSF200, PSF300, PSF500, PSF750,
psf1280, psf1920, psf2560, psf0-v1020,
spare9, spare8, spare7, spare6,
spare5, spare4, spare3, spare2,
spare1},
drx-RetransmissionTimer ENUMERATED {
psf1, psf2, psf4, psf6, psf8, psf16,
psf24, psf33},
longDRX-CycleStartOffset CHOICE {
sf10 INTEGER(0..9),
sf20 INTEGER(0..19),
sf32 INTEGER(0..31),
sf40 INTEGER(0..39),
sf64 INTEGER(0..63),
sf80 INTEGER(0..79),
sf128 INTEGER(0..127),
sf160 INTEGER(0..159),
sf256 INTEGER(0..255),
sf320 INTEGER(0..319),
sf512 INTEGER(0..511),
sf640 INTEGER(0..639),
sf1024 INTEGER(0..1023),
sf1280 INTEGER(0..1279),
sf2048 INTEGER(0..2047),
sf2560 INTEGER(0..2559)
},
shortDRX SEQUENCE {
shortDRX-Cycle ENUMERATED {
sf2, sf5, sf8, sf10, sf16, sf20,
sf32, sf40, sf64, sf80, sf128, sf160,
sf256, sf320, sf512, sf640},
drxShortCycleTimer INTEGER (1..16)
} OPTIONAL -- Need OR
}
}
DRX-Config-v1130 ::= SEQUENCE {
drx-RetransmissionTimer-v1130 ENUMERATED {psf0-v1130} OPTIONAL, --Need OR
longDRX-CycleStartOffset-v1130 CHOICE {
sf60-v1130 INTEGER(0..59),
sf70-v1130 INTEGER(0..69)
} OPTIONAL, --Need OR
shortDRX-Cycle-v1130 ENUMERATED {sf4-v1130} OPTIONAL --Need OR
}

RRM - Config field descriptions ue - InactiveTime
Duration while UE has not received or transmitted any user data. Thus the timer is still running in case eg, UE measures the neighbor cells for the HO purpose. Value s1 corresponds to 1 second, s2 corresponds to 2 seconds and so on. Value min1 corresponds to 1 minute, value min1s20 corresponds to 1 minute and 20 seconds, value min1s40 corresponds to 1 minute and 40 seconds and so on. Value hr1 corresponds to 1 hour, hr1min30 corresponds to 1 hour and 30 minutes and so on.

-- ASN1START
RRM-Config ::= SEQUENCE {
ue-InactiveTime ENUMERATED {
s1, s2, s3, s5, s7, s10, s15, s20,
s25, s30, s40, s50, min1, min1s20c, min1s40,
min2, min2s30, min3, min3s30, min4, min5, min6,
min7, min8, min9, min10, min12, min14, min17, min20,
min24, min28, min33, min38, min44, min50, hr1,
hr1min30, hr2, hr2min30, hr3, hr3min30, hr4, hr5, hr6,
hr8, hr10, hr13, hr16, hr20, day1, day1hr12, day2,
day2hr12, day3, day4, day5, day7, day10, day14, day19,
day24, day30, dayMoreThan30} OPTIONAL,
...,

For the differential setting and application operation of the C-DRX waiting period of 4G and 5G described above, according to an embodiment, drx-Config, drx included in the MAC-MainConfig field configured between the terminal and the base station described in Tables 1 to 4 -InactivityTimer, drx-RetransmissionTimer, drxShortCycleTimer parameters and the setting values corresponding to the ue-InactiveTime parameter and sub-parameter of the RRM-Config field are not one set in 5G, but an LTE set (or low/lower frequency, or sub- 6GHz link) and NR set (or high/higher frequency, or above-6GHz link) can be set separately and applied to operate.

For example, by setting a separate drx set for 5G in the MAC-MainConfig field and the RRM-Config field as shown in Tables 5 and 6 below, the UE differentiates the C-DRX waiting period of 4G and 5G differently. It becomes possible to set up and operate it. In Tables 5 and 6, a parameter constituting a new drx set for 5G is indicated by adding 'nr'. Here, the parameters shown in Tables 5 and 6 are merely examples, and in order to operate C-DRX between 4G and 5G differently, other parameters may be additionally set. Conversely, some parameters are omitted in the described embodiment. The parameters may be set in the form. As one method for operating C-DRX differently between 4G and 5G, parameters to which 'nr' is added for 5G connection may be set to shorter or longer values than parameters for 4G connection, and some parameters are the same It can also be set to a value.

DRX-Config ::= CHOICE {
release NULL,
setup SEQUENCE {
onDurationTimer ENUMERATED { },
drx-InactivityTimer ENUMERATED { },
drx-RetransmissionTimer ENUMERATED { },
longDRX-CycleStartOffset CHOICE { },
shortDRX SEQUENCE {
shortDRX-Cycle ENUMERATED{ },
drxShortCycleTimer INTEGER (1..16)
} OPTIONAL -- Need OR
}
}
DRX-Config-v1130 ::= SEQUENCE {
drx-RetransmissionTimer-v1130 ENUMERATED {psf0-v1130} OPTIONAL, --Need OR
longDRX-CycleStartOffset-v1130 CHOICE {
sf60-v1130 INTEGER(0..59),
sf70-v1130 INTEGER(0..69)
} OPTIONAL, --Need OR
shortDRX-Cycle-v1130 ENUMERATED {sf4-v1130} OPTIONAL --Need OR
}
DRX-Config-nr ::= SEQUENCE {
onDurationTimer_nr ENUMERATED { },
drx-InactivityTimer_nr ENUMERATED { },
drx-RetransmissionTimer_nr ENUMERATED { },
longDRX-CycleStartOffset_nr CHOICE { },
shortDRX_nr SEQUENCE {
shortDRX-Cycle_nr ENUMERATED{ },
drxShortCycleTimer_nr INTEGER (1..16)
}

-- ASN1START
RRM-Config ::= SEQUENCE {
ue-InactiveTime ENUMERATED { } OPTIONAL,
...,
RRM-Config_nr ::= SEQUENCE {
ue-InactiveTime_nr ENUMERATED { } OPTIONAL,
...,

In the process of dually setting C-DRX parameters for 4G connection and 5G connection according to the above-described embodiment, various criteria may be applied. First, when the parameters are divided based on the communication generation, the parameters are divided based on the 4G connection and the 5G connection. Second, parameters may be divided for each frequency band. For example, it is also possible to set the related parameters for a link of a frequency band of 6 GHz or less and a link of a frequency band of 6 GHz or more. Third, it is also possible to set the parameter by binary depending on whether or not beamforming is performed. Fourth, the method to set the parameter by binary setting based on the threshold value of the number of beams (wide beam and narrow beam), and finally, a method with high power efficiency It is also possible to set the parameters by dualizing them based on the modem and the low modem. Of course, in the process of setting the C-DRX related parameters in a binary manner according to the various criteria described above, an embodiment in which two or more criteria are complexly applied is possible.

According to the above-described embodiment, the dually set parameters are the drx-Config, drx-InactivityTimer, drx-RetransmissionTimer, drxShortCycleTimer parameters and RRM-Config fields corresponding to the MAC-MainConfig field related to the Connected DRX (C-DRX) illustrated above. Of course, ue-InactiveTime may be included, and other parameters may be added or some parameters may be excluded.

According to the above-described embodiment and another embodiment, a user-inactivity timer, which is a timer for RRC state transition of the terminal, may be differentiated for each 4G/5G link, and may be set and operated. The user-inactivity timer is a parameter related to the CP tail and radio tail described above. When the user-inactivity timer expires, the UE releases the RRC connection and operates in the RRC idle state. At this time, for example, when the base station implements and applies User-inactivity timer_1 and User-inactivity timer_2 as separate parameters or configures the terminal, the terminal automatically connects RRC without signaling to the base station when the corresponding timer expires. may be released (autonomous release) and transition to an idle state or an inactive state.

That is, the above-described process can be separately applied to the timer that is the criterion for transitioning from the RRC connected state to the idle state and the timer that is the criterion for the transition from the RRC connected state to the inactive state. When the corresponding timer expires, RRC signaling (each RRC release or RRC inactivation signaling) may mean an operation of transitioning the RRC state from Connected to Idle or Inactive state.

On the other hand, in this embodiment, the user-inactivity timer is set by a) dually for 4G link and 5G link, or b) for each frequency band by dualizing related parameters for frequency band link below 6 GHz and link above 6 GHz frequency band, or , c) It is set by dualizing the relevant parameters depending on whether or not beamforming is performed, d) It is set by dualizing the relevant parameters based on the threshold value based on the number of beams (wide beam and narrow beam), or e) The modem with high power efficiency and the low Modem-based related parameters may be set up by dualizing them, and parameters may be set up by dualizing them through a combination of two or more of the above-mentioned criteria.

In the embodiment described above, in the embodiment in which the DRX and inactivity timer sets of HF and LF are differentiated and set and operated, a method in which the base station sets and operates the corresponding parameters to fixed values is also possible.

According to another embodiment, whether it is within the coverage of the SN (Secondary Node) base station, service information of traffic and QoS required by the service, data capacity of traffic and the state (amount) of the buffer accumulated in the terminal/base station, PDCP Duplication It is also possible to determine and set parameters related to DRX and inactivity timer based on each of the activation status, movement speed and mobility support requirements of the terminal, and a combination of two or more. That is, when the terminal is within the coverage of the SN (Secondary Node) base station, the service information of traffic and QoS required by the service are low-delay or high-capacity, or the data capacity of traffic and the amount of buffer accumulated in the terminal/MN or SN base station When the threshold value is higher than the threshold, when PDCP duplication operation is activated and PDCP packets are transmitted/received through both MN and SN links, and each and a plurality of conditions based on mobility support (Handover and Radio Link failure performance requirements) according to terminal movement speed You can set and apply an event trigger defined by a combination of these.

Furthermore, an embodiment in which values of the C-DRX parameter and user inactivity timer for the SN link are determined and set conservatively based on the above contents may be considered, and the values of the C-DRX parameter and user inactivity timer for the MN link are also considered. An embodiment in which a conservative decision is made and set may be considered. Here, conservative determination and setting means setting a relatively long user inactivity timer, a method of setting drx-Config, drx-InactivityTimer, which are sub-parameters of C-DRX, a relatively long method, and setting a relatively long drx-RetransmissionTimer. method, and a method of setting drxShortCycleTimer to be relatively long.

According to the embodiment described above, when no traffic occurs in state 530 in FIG. 5 , the terminal enters the C-DRX mode according to the 5G C-DRX parameter ( 540 ). Subsequently, when the CP tail of a relatively shorter 5G connection expires according to the user-inactivity timer configured to be dualized, the UE first enters the 5G discovery state ( 550 ). That is, the CP Tail is operated relatively short for the 5G connection, so that the power consumption of the terminal consumed for the 5G connection can be reduced. Subsequently, when the user-inactivity timer set for the 4G connection of the terminal expires and the RRC connection is released, the terminal operates in the RRC idle state (560). At this time, since the terminal has one RRC state at a time even if a plurality of modems supporting different RATs are driven, all RRC connections except for the RRC idle state 560 in which all modems for 4G connection and 5G connection are turned off become a state

As the detailed operation scenario described above, 1) 5G link activation necessity and availability detection operation (510, 520) 2) 5G modem activation time determination operation (520, 530) 3) 4G and 5G C-DRX waiting period in RRC Connected state As another embodiment for implementing the differential setting and application operation 570, i) introduction of extended long-period discovery RS (reference signal) design for low-power operation of the terminal, and ii) 5G (NR) link It is also possible to operate 4G LTE link C-DRX or Idle DRX when activated. At this time, in the method of setting the LTE DRX cycle according to the mobile speed and latency requirements of the terminal, if the terminal is in a low-speed movement state and the latency requirement is not low delay and allows some delay, C-DRX or Idle DRX operation is performed. Methods may also be implemented.

6 is an RRC connection management method for low power of a terminal, and is an example of an operation of a terminal modem for each state according to an operation scenario for multi-RAT (4G, 5G) low power operation in an LTE-5G Tight Integration operating environment. FIG. 6 shows the operation scenarios of the terminal according to each case by dividing the operation of the 4G modem and the 5G modem of the terminal by the number of cases.

A more detailed operation of the terminal is described as follows. The terminal may operate in four modes depending on whether the multi-RAT modem (4G, 5G) is activated.

(Mode 1) a mode for turning off the 5G cell modem operation of the terminal, a terminal operation mode for receiving a control signal and data through a 4G LTE link;

(Mode 2) Partially turn on the 5G cell modem of the terminal with a long cycle (TP1) to check whether the 5G cell reception signal is within the 5G cell coverage based on whether the 5G cell reception signal is above a threshold (Discovery operation) Terminal operation mode ;

(Mode 3) Mode in which the terminal transmits feedback for handover and cell selection by measuring the average channel quality for each 5G cell (RU/TRP/ID) by turning on the 5G cell modem of the terminal at an intermediate cycle (TP2)

(Mode 4) Turn on the 5G cell modem of the terminal in a short period (TP3) to measure and feedback 5G cell channel quality and best beam, and information for transmission and reception with Dedicated (RU/TRxP/Cell ID) It includes a terminal operation mode to feedback.

Here, it is assumed that the modem operation period of the terminal is (TP1> TP2> TP3> 0).

Separately from the above four operation modes of the terminal, the following operation mode change condition (Triggering Event) may be set for measurement operation options in the discovery process of the terminal.

First, an event according to the relationship between the movement of the terminal and the 5G coverage may be set. For example, the event according to the relationship between the movement of the terminal and the cell coverage is (1-1) the event that the terminal moves within 5G coverage, (1-2) the event that the terminal moves out of the 5G coverage, and (1-3) the terminal It may include an event (triggering event) moving to the 5G coverage cell center. In this embodiment, the determination of whether 5G coverage is i) an operation of determining based on the network (N/W) information (eg, ANDSF, MME pre-configuration information) based and the message structure of the pre-configuration information, ii) In the Multi-RAT terminal, Tight-Interworking or Multi-Link operation may include Indication Message-based operation of Legacy RAT BS. For example, it includes an operation of designing a new message structure (New field) such as a 1-bit 5G cell indicator in the RRC connection response message, setting it by the base station, signaling to the terminal, and applying it to the terminal. In addition, iii) includes operating based on the received signal from the Legacy RAT BS in which Tight-Interworking or Multi-Link is operated in the Multi-RAT terminal. It goes without saying that 5G coverage can be determined by combining the aforementioned three criteria i), ii), and iii).

Second, the event operation may be set based on the buffer size in the terminal. The corresponding buffer may correspond to all PDCP/RLC/MAC/PHY buffers in the terminal, and the corresponding buffer may correspond to all PDCP/RLC/MAC/PHY buffers for each terminal supported by the base station of Legacy RAT and New RAT. . Hereinafter, events according to the buffer sizes of the terminal and the base station are divided into the number of cases and described in detail.

(2-1) Event where the traffic buffer of the terminal is zero

Event in which the terminal's traffic buffer exceeds the threshold TH1_21

Event in which the traffic buffer of the terminal exceeds the threshold TH2_21

(Full buffer> TH2_21> TH1_21> 0)

(2-2) (Legacy RAT) Event where the traffic buffer for each terminal of the base station is zero

(Legacy RAT) Event with traffic buffer amount of TH1_22 or more for each terminal of the base station

(Legacy RAT) Event with traffic buffer amount of TH2_22 or more for each terminal of the base station

(Full buffer> TH2_22> TH1_22> 0)

(2-3) (New RAT) Event in which the traffic buffer amount for each terminal of the base station is zero

(New RAT) Event with traffic buffer amount of TH3_23 or more for each terminal of the base station

(New RAT) Event with traffic buffer amount of TH4_23 or more for each terminal of the base station

(Full buffer> TH4_23> TH3_23> 0)

Third, an Event based on required QoS information may be set. According to this embodiment, the triggering event based on the required QoS information operates based on the QoS requirements of the service created in the terminal or server (base station), and the service is Traffic/Bearer/logical CH/RAN Slice (PHY/ MAC Resource/Configuration combination) and may operate based on the combination. Hereinafter, the triggering event will be classified and described based on the required QoS information.

(3-1) Required QoS is Link Data rate

Event where the required data rate is higher than threshold TH1_31

Event where the required data rate is higher than threshold TH2_31

(TH2_31 > TH1_31 > 0)

(3-2) Required QoS is Latency

Events with required latency below threshold TH1_32

Events with required latency below threshold TH2_32

(TH2_32 > TH1_32 > 0)

(3-3) Required QoS is Mobility support

Event with terminal movement speed greater than threshold TH1_33

Event where the required RLF (Radio Link Failure) is less than or equal to the threshold TH2_33

It includes an event where the required HO latency is less than or equal to the threshold TH3_33.

Fourth, the triggering event based on the recent traffic transmission/reception time is the subframe time of the PDCCH (Physical Downlink Control Channel) recently received by the terminal/base station, the time when the terminal buffer is Zero, and the (Legacy and/or New RAT) base station It can be set to each of the time points when the buffer for each terminal is zero or to a combination of two or more events. In this embodiment, the triggering event includes a reference time point and the elapse of a predetermined time after the reference time point.

(4-1) Event that exceeds the critical time after the terminal buffer is zero

Events above threshold TH1_41

Events above threshold TH2_41

(TH2_41 > TH1_41 > 0)

(4-2) (Legacy RAT) Event that exceeds the threshold time after the traffic buffer for each terminal of the base station is zero

Events above threshold TH1_42

Events above threshold TH2_42

(TH2_42 > TH1_42 > 0)

(4-3) (New RAT) Event that exceeds the threshold time after the traffic buffer amount for each terminal of the base station is zero

Events above threshold TH1_43

Events above threshold TH2_43

(TH2_43 > TH1_43 > 0)

6 shows the operation mode change triggering event of the terminal according to the various conditions described above (cell coverage, buffer status, required QoS information, elapsed time from the latest traffic arrival time) according to each and combination of the terminal. An operation for a 5G cell and operations for changing and transitioning a connection state are shown.

As an example of the operation, as shown in FIG. 6, the 5G cell modem operation of the terminal is in the 5G cell modem OFF state in the above-described mode 1 during initial access, and then transitions to the 5G cell discovery state based on the 5G cell coverage event (mode 2), Afterwards, the buffer size-based Event (TH1_2x) or/and (TR1_3x) and/or the combination of the required QoS information-based Event (TH1) transitions to the 5G cell measurement mode (mode 3), and the buffer size-based Event (TH2_2x) and/or (TR2_3x) By combining the required QoS information-based Event (TH1), detailed measurement of 5G cell channels or switching to continuous active mode (mode 4) can be performed.

7 is a control signal flow for multi-RAT (4G, 5G) low power operation in an LTE-5G Tight Integration operating environment as an RRC connection management method for low power of a terminal in a communication system according to an embodiment of the present invention; ) and a diagram for explaining an example of an operation process of a base station/terminal.

First, in a state in which the 5G modem of the terminal is deactivated (S760), an indicator indicating information on 5G coverage is transmitted to the terminal from the base station supporting the 4G connection of the terminal (S705), and the terminal performs a 5G discovery procedure while performing a short CP Receives parameters to set the tail. This short CP tail related parameter may be a parameter for differentially setting and operating the 4G/5G C-DRX waiting period as described above.

Subsequently, the UE performs a beam training procedure ( S710 ) through a 5G cell measurement procedure through a 5G discovery procedure ( S765 ), and feeds back information on the scanned optimal beam to the 5G base station ( S715 ). In this case, a triggering event for the terminal to initiate the 5G discovery procedure may occur based on the amount of the buffer of the base station (S720). When the 5G discovery procedure of the terminal is completed, the 4G base station instructs the terminal to add a 5G cell (S725), and a connection between the 5G base station, which is a cell of the mmW band, and the terminal is established (S770). When the terminal exchanges data through the connection with the 5G base station (S730) and operates with C-DRX, when the short CP tail configured for the 5G connection expires (S735), the connection with the 5G cell is released (S740) It operates in the 5G discovery state (S775). On the other hand, when the CP tail for the 4G connection of the terminal also expires (S745), the terminal releases the connection with the 4G base station (S750) and operates in the RRC idle mode waiting for paging from the 4G base station (S755).

In the above process, the buffer amount threshold (TH1) of the triggering event for the terminal to initiate 5G cell measurement and the buffer amount threshold (TH2) of the triggering event for the MR (Measurement Report) in which the terminal reports the measurement result to the base station ) can be set differently. When the UE/base station RLC Buffer is greater than or equal to the threshold value TH2 in a situation where UE UL transmission is required, an MR (Measurement Report) transmission operation is performed, which is an operation that consumes UE UL transmission power. Since the MeNB, which is 4G LTE, determines the cell addition, the UE performs an operation of performing measurement and transmitting only MR (Measurement Report).

In the above, the operation in the LTE-5G tight integration environment, that is, the NSA environment, has been mainly described. An operation in an LTE-5G independent environment (ie, an SA environment) will be described with reference to FIG. 8 below.

8 is a control plane (Control plane: CP) and a user plane (User plane: UP) between a core network and a base station in an LTE-5G independent environment based on ML (Multi-Link) in a communication system according to an embodiment of the present invention. It is a diagram showing an example of a connection state. In this environment, the LTE base station and the 5G (NR) base station operate independently. At this time, when the 4G and 5G core networks exist separately but an interface exists between each other, or when the 4G and 5G core networks exist separately and there is no interface between them, or the 4G core network evolves and the 5G core network together (merge) All cases of use can be included. Since the LTE base station and the 5G (NR) base station operate independently, in the case of a 4G (LTE) link, both the control plane (CP) and the user plane (UP) between the terminal and the base station can be connected, and 5G Even in the case of (NR), it can be considered that both a control plane (CP) and a user plane (UP) between the terminal-base station are connected.

9 is a diagram illustrating an example of a connection state between base stations and signaling between protocol layers in an LTE-5G independent environment (Multi-Link: ML) in a communication system according to an embodiment of the present invention. In this environment, since the LTE base station and the 5G (NR) base station operate independently, it is possible for the 4G and 5G protocol layers to operate as independent protocol layers for the RRC, PDCP, RLC, MAC, and PHY layers.

10 is a diagram illustrating a state diagram for multi-RAT (4G, 5G) low-power operation in an LTE-5G independent operating environment according to an embodiment of the present invention.

In the LTE-5G independent operating environment, 4G and 5G connections are independently controlled (including paging), and this control operation includes a Paging RAT selection process based on the cell coverage in which the UE is located. In addition, in the LTE-5G independent operating environment, flow aggregation can be supported at the gateway stage, and each connection of 4G/5G determines whether traffic/Coverage/QoS support for the terminal is required and based on this, whether to activate Multi-Link (1020) It is possible to determine whether to activate a single link (5G only or 4G only) (1010, 1030) and perform an application operation.

This process can be operated based on the coverage of the cell in which the terminal is located. Specifically, based on the 4G cell/5G cell reception signal level or the coverage-related indication from the network, the operation of determining according to each criterion and combination is performed. can Alternatively, whether to operate based on the type of High Quality Traffic (eg, VoIP, new URLLC service, etc.) to be supported in the terminal, or to determine based on the state of the buffer in the base station / terminal based on the QoS situation is performed. may be

11 is a diagram illustrating an example of terminal modem operation for each state according to an operation scenario for multi-RAT (4G, 5G) low-power operation in an LTE-5G independent operation environment according to an embodiment of the present invention.

The RRC state operation of the multi-RAT capable terminal may exist in the following four states.

(ST1: state 1, state 1) Legacy RAT RRC_Connected / New RAT RRC_Idle

(ST2) Legacy RAT RRC_Connected / New RAT RRC_Connected

(ST3) Legacy RAT RRC_Idle / New RAT RRC_Connected

(ST4) Legacy RAT RRC_Idle / New RAT RRC_Idle

Here, the RRC_Connected state is again divided into a continuous reception mode and a C-DRX mode, and the RRC_Idle state is subdivided into an idle DRX (paging) step and an inactive mode that turns off the entire modem circuit.

Multi-RAT capable terminals operating in four different states are New RAT (5G) events according to cell coverage (TR1: event 1, TRiggering event 1), Buffer conditions (buffer size) event (TR2), The event (TR3) according to the presence or absence of High QoS Traffic and the Event (TR4) based on the required QoS information can be operated as a condition of each or a combination of two or more. Such a multi-RAT capable terminal may operate as follows while changing the above-described RRC state according to an event according to the various conditions described above.

In the LTE-5G (MN-SN) independent, that is, in the SA environment, after the 5G discovery process is terminated, the UE determines the 5G modem activation time (determining the 5G ON time) to support mobility according to the UE movement speed (Handover Failure, It includes the action of determining when to activate the 5G modem based on performance requirements for handover latency and radio link failure). In one embodiment, when the terminal movement speed is high and the threshold value (for example, 120 km/h) or more and the handover latency requirement is less than the threshold value (for example, 1 second or 0), it operates only with the MN link and does not activate the SN , or the operation of performing data transmission to the continuously activated SN without deactivating the SN. It also includes the operation of performing the mobility support of the terminal through the continuously activated MN without deactivating the MN.

(ST1) Legacy RAT RRC_Connected/ New RAT RRC_Idle: If the buffer size is greater than or equal to the TR2-based threshold or the required QoS (data rate, latency requirements) is greater than or equal to the threshold of TR3, the 5G cell is activated and operates as ST2

(ST2) Legacy RAT RRC_Connected / New RAT RRC_Connected: Depending on the 5G coverage event (TR1), if the QoS required in the 5G-centric coverage area situation is less than or equal to the (mobility requirement, terminal movement speed) threshold or meets at least one (TR3) Deactivate 4G cell and operate as ST3

(ST3) Legacy RAT RRC_Idle / New RAT RRC_Idle: As an event based on the recent traffic transmission/reception time, if more than the threshold time elapses, the 5G cell and 4G cell are deactivated and ST4 is operated.

(ST4) Legacy RAT RRC_Idle / New RAT RRC_Idle: Since the Multi-RAT capable UE Paging can support both RATs, it operates while selectively receiving either the New RAT or the Legacy RAT.

In the LTE-5G interworking and NSA environment, the UE operates to receive LTE (4G) paging in the RRC idle state, but in the LTE-5G independent, SA environment, it may operate to receive paging based on the recently activated recent RAT. That is, the multi-RAT capable terminal may arbitrarily select any one of the two RATs and operate while receiving the paging message, or may select the most recently terminated RAT to receive the paging message and operate.

According to the above-described embodiment, the operation for minimally controlling the RRC_Connected state in the 5G cell of the multi-RAT capable terminal may be applied even in the SA environment. That is, the RRC State connection control of the multi-RAT capable terminal may include a process of operating the CP tail for New RAT (NR) relatively shorter than the CP tail for the legacy RAT, and according to an embodiment, to the New RAT It includes the operation of switching to RRC Idle state immediately after NR traffic transmission/reception is completed by designing the CP Tail close to Zero(0) + margin (Margin << 1).

At this time, whether paging reception or non-received idle state operation for NR is performed is determined according to the LTE-5G interworking environment and LTE-5G independent environment, and information related to the paging operation is determined by the Multi-RAT terminal at the first N/ When accessing W (a core network such as ANDSF or MME can be delivered to the terminal in a way that notifies the terminal through the Legacy RAT or New RAT base station.

Hereinafter, reference conditions for shortening/extending the RRC State will be described. First, embodiments for shortening the RRC connection will be described. In order for the 5G base station/terminal to stop the RRC_Connected state of the corresponding 5G cell earlier than the initially set Timer and to switch the terminal to idle mode or no paging reception mode:

(ST1) RRC release message immediate transmission operation of the base station,

(ST2) Terminal's Fast Dormancy Request Message Transmission Operation

(ST3) At least one of a Power Preference Indicator (PPI) message transmission operation of the terminal may be performed.

Conversely, embodiments for delaying the RRC connection will be described. 5G base station/terminal extends the RRC_Connected state of the corresponding 5G cell beyond the initially set Timer and enters the early idle state due to CP tail shortening. To minimize overhead and terminal power consumption:

(SUS1) base station RRC release message transmission delay operation;

(SUS2) terminal new RRC Suspend request message transmission operation; and

(SUS3) It is possible to perform at least one of the timer extension operations by transmitting the terminal dummy data.

In the embodiment described above, in an embodiment in which DRX and inactivity timer sets for HF and LF cells are differentiated and set and operated in an SA environment, a method in which the base station sets and operates the corresponding parameter to a fixed value is also possible.

According to another embodiment, whether or not the SN (Secondary Node) is within the coverage of the base station, service information of traffic and QoS required by the service, data capacity of traffic and the state (amount) of the buffer accumulated in the terminal/base station, the state (amount) of the terminal It is also possible to determine and set parameters related to DRX and inactivity timer based on each of the movement speed and mobility support requirements and a combination of two or more. That is, when the terminal is within the coverage of the SN (Secondary Node) base station, the service information of traffic and QoS required by the service are low-delay or high-capacity, or the data capacity of traffic and the amount of buffer accumulated in the terminal/MN or SN base station An event trigger defined by a combination of each condition and a plurality of conditions based on mobility support (Handover and Radio Link failure performance requirements) according to the case of exceeding the threshold value and the terminal movement speed can be set and applied.

Furthermore, an embodiment in which values of the C-DRX parameter and user inactivity timer for the SN link are determined and set conservatively based on the above contents may be considered, and the values of the C-DRX parameter and user inactivity timer for the MN link are also considered. An embodiment in which a conservative decision is made and set may be considered. Here, conservative determination and setting means setting a relatively long user inactivity timer, a method of setting drx-Config, drx-InactivityTimer, which are sub-parameters of C-DRX, a relatively long method, and a method of setting a relatively long drx-RetransmissionTimer. method, may mean a method of setting drxShortCycleTimer to be relatively long.

12 is a view for explaining an example of a control signal flow for multi-RAT (4G, 5G) low-power operation and an operation process of a base station/terminal in an LTE-5G independent operating environment according to an embodiment of the present invention; am.

First, in a state in which the 5G modem of the terminal is deactivated and only the 4G modem is activated (S1260), a paging message is transmitted to the terminal from the base station supporting the 4G connection of the terminal (S1200). When the UE recognizes the need to activate 5G connection according to a triggering event (S1205) that compares the amount of buffer with a predetermined threshold value TH1, it performs a 5G discovery procedure (S1265), and beams to a base station supporting 5G connection A forming RACH (Random Access CHannel) procedure is performed (S1210).

When the connection between the terminal and the 5G base station is established and the buffer amount of the terminal is compared with another threshold value TH2 and satisfies the triggering event (S1215), the terminal adds a 5G cell and sends and receives data through the connection with the 5G base station ( S1220, S1225). In this process, only the 5G connection of the terminal is activated, and the 4G modem may operate in the RRC idle state (S1270). On the other hand, when a predetermined time elapses after the data transmission through the 5G connection of the terminal is completed (S1230), the 5G modem of the terminal is turned off through the 5G cell release process of the terminal (S1235). This time may be a time interval corresponding to the short CP tail described above.

When the 4G connection of the terminal is in the RRC idle state and in the 5G discovery state (S1275), the terminal receives the 5G paging message (S1240), and when the time period for the 4G connection expires (S1245) The connection with the 4G cell of the terminal is also released and (S1250), the terminal operates in a state of receiving the 4G paging message (S1255).

An operation of reducing the terminal connection latency based on a traffic end point (TCP flag FIN) for an efficient 5G Radio Tail (User Inactivity timer) period reduction operation according to an embodiment of the present invention will be described below. FIG. 13 is an embodiment of the present invention An example of a terminal connection latency reduction operation based on a traffic end point (TCP flag FIN) is shown for an efficient 5G Radio Tail (User Inactivity timer) period reduction operation according to the example, and the FIN (final ) display and ACK transmission to confirm it.

TCP is a protocol of the transport layer, and TCP creates a TCP segment by segmenting data received from a data stream and adding a TCP header. TCP makes data exchange between network nodes stable and error-free, and when the sending node sets the FIN flag to 1 bit among the flags 1410 included in the TCP header and transmits, there is no more data to be transmitted from the sending side; That is, it means the end of the transmission. The receiving node that receives the FIN flag set to 1 sets the ACK flag to 1 bit and transmits it as a response.

14 is a base technology for showing an example of a terminal connection latency reduction operation based on a Traffic end point (TCP flag FIN) for an efficient 5G Radio Tail (User Inactivity timer) period reduction operation according to an embodiment of the present invention. It is a type of flag indicated in the TCP header and includes a FIN indicating the end of transmission.

15 is a base technology for showing an example of a terminal connection latency reduction operation based on a traffic end point (TCP flag FIN) for an efficient 5G Radio Tail (User Inactivity timer) period reduction operation according to an embodiment of the present invention. It is a diagram showing a hierarchical structure and a unit in a wireless communication protocol.

A TCP-related embodiment will be described in detail. The UE Inactivity Timer (CP Tail) for the 5G cell according to the above-described embodiment may be set to various criteria (Criterion). For example, according to the first criterion, the UE inactivity timer (CP tail) is set based on the traffic end point (TCP flag FIN) so that when a FIN value, which is one of the TCP Header flags (6bit), is received, the connection is terminated early. It may be set or set to maintain the connection until an ACK flag value is received as a response to the FIN flag, and further set and operate to extend the connection based on the SYN value, which is another flag value among TCP Header flags (6bit) You may.

In order to check the TCP flag of the IP (TCP) traffic, when the PDCP implemented in the terminal CP is generated, the information of the corresponding flag can be identified by performing TCP header parsing of the IP (TCP) traffic header information implemented in the AP of the terminal. If the total number of TCP connections among the plurality of TPC connections is 0, the terminal transmits a terminal feedback, for example, a Power Preference Indicator (PPI), so that the base station shortens the Radio Tail (ie, performs RRC Release).

In this case, the terminal and the base station may perform a PPI determination operation based on the number of TCP connections through IP (TCP) flag parsing in order to manage the total number of TCP connections among the plurality of TPC connections. If the total number of TCP connections is 0 through TCP Connection Request (SYN) Flag-based increase (++) operation and TCP Connection Termination (FIN) Flag-based number decrease (--) operation, the above-described RRC release operation is performed.

As another method, the base station performs TCP Header Parsing to determine the information of the corresponding flag. In this case, it is of course also possible to perform a radio tail shortening operation by performing RRC Release of the base station without transmitting terminal feedback.

Hereinafter, an embodiment in which it is necessary to extend the 5G connection of the terminal while minimizing the 5G connection of the terminal because the CP tail is shortened according to the embodiment described above will be described. In the operation of the terminal feeding back information on whether or not data is requested to the server to the base station and using it for CP tail control, download traffic (eg, e-mail confirmation pull, push service, etc.) is scheduled from the server after the UL traffic transmission request. A method of extending the CP tail by notifying the UE will be described. For example, i) whether DL data is transmitted after the corresponding UL data, ii) whether ACK/NACK reception is required, iii) keep alive message only, iv) server update (accompanied by DL transmission), etc. to extend the 5G connection of the terminal. may be conditions for, and a combination of two or more of the above conditions is also possible. The base station may reflect and utilize information indicating these criteria in the DRX cycle and radio tail adjustment process.

Conversely, the method of transmitting whether DL traffic is generated as a server operation according to the UE's request (UL) is based on new/existing control signaling i) A method of indicating in the new field of the existing MAC Control Element, BSR (Buffer Status Report) A method of marking the New Field or ii) an operation of marking and transmitting the UL Data MAC Header may be performed.

16 is a diagram illustrating an example of a DL Traffic generation-based operation as a server operation according to a terminal request (UL) for a control operation of minimizing a 5G CP tail section according to an embodiment of the present invention.

New/existing control signaling design is required according to the need to send feedback to the base station whether the terminal requests data. When an uplink grant is received from the base station following transmission of a scheduling request (SR) and a buffer status report (BSR) from the terminal (S1610, S1620, S1630, S1640), the terminal requests DL traffic transmission while transmitting UL data (S1650) ), and the base station transmits downlink data to the terminal accordingly (S1660). The transmission/reception process between the terminal and the base station can be performed by i) a method of indicating in the new field of the existing MAC Control Element, for example, indicating whether the terminal requests data in the BSR (Buffer Status Report) New Field, ii ) may be operated as a method of marking the UL Data MAC Header. As such, by piggybacking or adding a new field to the existing signal, whether the terminal transmits DL data after the corresponding UL data, whether ACK/NACK reception is necessary, keep alive message only, Server Update (accompanying DL transmission) each and two Information on the above combinations may be transmitted to the base station. Accordingly, the base station controls the waiting time (Radio Tail) from the C-DRX and Idle DRX cycles and the last transmission/reception traffic for the corresponding link based on the received information, and can control the terminal by setting and applying it.

17 is a diagram illustrating a DL Traffic generation-based operation as a cost-based server operation of a process in which a terminal transitions from an RRC Idle state to an RRC Connected state for a 5G CP Tail section minimization control operation according to an embodiment of the present invention. .

When a short tail is set and operated as a cost-based operation of the RRC state transition process of the UE, there may occur problems in signaling load increase and QoE degradation when traffic prediction is impossible. Specifically, these problems include: i) the burden of setting up a terminal request transmission and disconnection of the base station, ii) power consumption due to terminal uplink transmission and control resource consumption when multiple terminals are operating, iii) reconnection after entering the idle state when the traffic pattern is unpredictable Setup burden, iv) LTE terminal-based transmission power consumption (523 mW), delay (1.4 sec: paging delay 1.28 sec, connection reset 84 ms delay expected), etc. may occur.

To compensate for this problem, even when RRC connection is released in the RRC Connected (1710) state, instead of immediately entering the RRC idle (1730) state, RRC minimizes the procedure required for the UE to transition to the RRC connected state. An inactive 1720 state (or light connection) may be introduced. This RRC inactive state is different from the RRC idle state in that the RRC connection is not completely released but is deactivated. At this time, it is necessary to design a 5G tail section minimization operation in consideration of the transition from the RRC inactive state to the RRC connected state again. More specifically, since the promotion (Promotion, transition to RRC Connected state) cost of the terminal changes depending on whether the network operates as legacy idle or RRC inactive state after RRC connected state, these costs are reflected in CP tail As the control operation, it is possible to implement a method of operating based on i) a delay occurrence time according to the N/W signaling overhead, and ii) the consumption of the base station terminal power for the corresponding procedure. On the other hand, instead of introducing the RRC inactive state according to the above-described embodiment, a network such as a base station may introduce an RRC Suspend State (ECM Connected State) that holds the context of the terminal, and resumes in the RRC suspend state. Through the procedure, it transitions to the RRC connected state.

According to an embodiment, in the Warming UP procedure, which is an operation required before data reception from Wake up (on operation) from sleep during DRX operation, Beamforming Synchronization operation, switching on hardware circuit including precise-clock, RF circuit with massive antennas and In consideration of the additional high speed core processor, it is possible to control and signal the C-DRX and Idle DRX cycles and the latency (Radio Tail) from the last transmission/reception traffic.

According to this embodiment, since the promotion cost is changed according to the terminal implementation and network configuration, promotion time and promotion energy related information can be added to the UE category information and the network can transmit it to the base station, and the base station performs RRC release based on this. can do.

In addition, the minimum idle period (ie, the minimum time maintained when switching to RRC Idle) can be determined based on the promotion cost related information, and the operation can be performed by delaying the transition to the RRC_Connected state. Accordingly, it is possible to ensure the power reduction effect of the terminal when the terminal enters the idle mode by applying the minimum Idle period maintained at least when the terminal switches to RRC Idle.

According to another embodiment, as a method of setting the CP Tail based on 5G Coverage Triggering, when there is no possibility that the UE is outside the 5G Coverage or within the 5G Coverage, the NR CP Tail is set to zero (if there is no possibility of being outside the 5G Coverage) or It can operate to disable paging (when there is no possibility of being within 5G coverage). In this embodiment, it is possible to operate based on information from Tight-Interworking or Multi-Link or Legacy RAT BS in the Multi-RAT terminal.

According to another embodiment, in the terminal/base station buffer-based CP tail setting method, as an embodiment of the terminal/base station buffer-based radio tail adjustment operation, when data exists in the terminal UL PDCP buffer, PPI transmission is postponed and the base station In addition to the operation of deferring the RRC Release when there is data in the DL PDCP Buffer, on the contrary, it is also possible to operate to execute the RRC Release early when there is no data in the UL PDCP Buffer and when there is no data in the DL PDCP Buffer of the base station.

18 is a diagram illustrating the structure of a terminal according to an embodiment of the present invention. Referring to FIG. 18 , the terminal may include a transceiver 1810 , a terminal controller 1820 , and a storage 1830 . In the present invention, the terminal control unit 1820 may be defined as a circuit or an application-specific integrated circuit or at least one processor.

The transceiver 1810 transmits and receives signals with other network entities. The transceiver 1810 may, for example, receive system information from a network entity (eg, a CU, DU, and/or a base station), and may receive a synchronization signal or a reference signal. The transceiver 1810 may be implemented in the form of an RF unit including a modem.

The terminal controller 1820 may control the overall operation of the terminal according to the embodiment proposed in the present invention. For example, the terminal control unit 1820 may control the transceiver 1810 and the storage unit 1830 to perform operations according to the embodiments described above with reference to the drawings. Specifically, the terminal control unit 1820 may set the UE inactivity timer differently for each RAT or activate/deactivate the modem included in the transceiver unit 1810 differently for each RAT according to an embodiment of the present invention.

The storage unit 1830 may store at least one of information transmitted and received through the transceiver 1810 and information generated through the terminal control unit 1820 . For example, the storage unit 1830 may store UE inactivity timer related information received through the transceiver 1810 .

19 is a diagram illustrating a structure of a base station according to an embodiment of the present invention. Referring to FIG. 19 , the base station may include a transceiver 1910 , a base station control unit 1920 , and a storage unit 1930 . In the present invention, the base station controller 1920 may be defined as a circuit or an application-specific integrated circuit or at least one processor.

The transceiver 1910 may transmit/receive signals to and from other network entities. The transceiver 1910 may transmit, for example, system information to the terminal, and may transmit a synchronization signal or a reference signal. The transceiver 1910 may be implemented in the form of an RF unit including a modem.

The base station controller 1920 may control the overall operation of the base station according to the embodiment proposed in the present invention. For example, the base station controller 1920 may control the transceiver 1910 and the storage unit 1930 to perform operations according to the embodiments described above with reference to the drawings. Specifically, the base station controller 1920 may establish or release an RRC connection with the terminal according to an embodiment of the present invention.

The storage unit 1930 may store at least one of information transmitted/received through the transceiver unit 1910 and information generated through the base station controller 1920 . For example, the storage unit 1930 of the CU/DU may store information or a value related to a UE inactivity timer, which is a waiting time to release an RRC connection with a UE.

On the other hand, in the present specification and drawings, preferred embodiments of the present invention have been disclosed, and although specific terms are used, these are only used in a general sense to easily explain the technical contents of the present invention and to help the understanding of the present invention. It is not intended to limit the scope of It will be apparent to those of ordinary skill in the art to which the present invention pertains that other modifications based on the technical spirit of the present invention can be implemented in addition to the embodiments disclosed herein.

Claims (20)

In a method for a terminal to transmit and receive a signal in a wireless communication system,
receiving, from a first base station, system information including an indicator used to determine that the terminal has entered a coverage area of a second base station;
Receiving, from the first base station, a radio resource control (RRC) connection reconfiguration message for setting the measurement for the cell of the second base station, the RRC connection reconfiguration message, the carrier frequency for the measurement comprising first information for confirming and second information for confirming a threshold value for the measurement;
performing the measurement on the cell of the second base station based on the first information and the second information; and
transmitting, to the first base station, the result of the measurement for the cell of the second base station;
The method of claim 1, wherein the first base station operates based on a first radio access technology, and the second base station operates based on a second radio access technology. delete According to claim 1,
The method further comprising the step of determining that the second base station is within the coverage of the first base station based on the indicator. According to claim 1,
The method further comprising the step of receiving, from the base station, a message for adding the cell of the second base station as a secondary cell group for the terminal based on a result of the measurement. According to claim 1,
The first radio access technology is long term evolution (LTE), and the second radio access technology is new radio (NR),
According to dual connectivity, the first base station operates as a master node (MN) for the terminal, and the second base station operates as a secondary node (SN) for the terminal. A method for a first base station to transmit and receive a signal in a wireless communication system, the method comprising:
transmitting, to the terminal, system information including an indicator used for determining that the terminal has entered the coverage area of a second base station;
Transmitting, to the terminal, a radio resource control (RRC) connection reconfiguration message for setting the measurement for the cell of the second base station, the RRC connection reconfiguration message is to check the carrier frequency for the measurement comprising first information for and second information for identifying a threshold value for the measurement; and
Receiving, from the terminal, the result of the measurement for the cell of the second base station based on the first information and the second information,
The method of claim 1, wherein the first base station operates based on a first radio access technology, and the second base station operates based on a second radio access technology. delete 7. The method of claim 6,
The terminal determines based on the indicator that the second base station is within the coverage of the first base station. 7. The method of claim 6,
The method further comprising the step of transmitting, to the terminal, a message for adding the cell of the second base station as a secondary cell group for the terminal based on a result of the measurement. 7. The method of claim 6,
The first radio access technology is long term evolution (LTE), and the second radio access technology is new radio (NR),
According to dual connectivity, the first base station operates as a master node (MN) for the terminal, and the second base station operates as a secondary node (SN) for the terminal. In a terminal for transmitting and receiving a signal in a wireless communication system,
a transceiver for transmitting and receiving a signal; and
controlling the transceiver to receive, from a first base station, system information including an indicator used for determining that the terminal has entered a coverage area of a second base station; Control to receive, from the first base station, a radio resource control (RRC) connection reconfiguration message for setting the measurement for the cell of the second base station, the RRC connection reconfiguration message, the carrier frequency for the measurement including first information for confirming and second information for confirming a threshold value for the measurement; perform the measurement on the cell of the second base station based on the first information and the second information, and transmit, to the first base station, a result of the measurement on the cell of the second base station Includes a control unit for controlling the transceiver,
The first base station operates based on a first radio access technology, and the second base station operates based on a second radio access technology. delete 12. The method of claim 11,
The control unit determines that the second base station is within the coverage of the first base station based on the indicator. 12. The method of claim 11,
The control unit controls the transceiver to receive, from the base station, a message for adding the cell of the second base station as a secondary cell group for the terminal based on the result of the measurement. terminal that does. 12. The method of claim 11,
The first radio access technology is long term evolution (LTE), and the second radio access technology is new radio (NR),
According to dual connectivity, the first base station operates as a master node (MN) for the terminal, and the second base station operates as a secondary node (SN) for the terminal. In a first base station for transmitting and receiving signals in a wireless communication system,
a transceiver for transmitting and receiving a signal; and
controlling the transceiver to transmit, to the terminal, system information including an indicator used for determining that the terminal has entered the coverage area of the second base station; Controls the transceiver to transmit, to the terminal, a radio resource control (RRC) connection reconfiguration message for setting the measurement for the cell of the second base station, the RRC connection reconfiguration message is a carrier for the measurement comprising first information for ascertaining a frequency and second information for identifying a threshold value for the measurement; a control unit for controlling the transceiver to receive, from the terminal, the result of the measurement for the cell of the second base station based on the first information and the second information,
The first base station according to claim 1, wherein the first base station operates based on a first radio access technology, and the second base station operates based on a second radio access technology. delete 17. The method of claim 16
The terminal determines that the second base station exists within the coverage of the first base station based on the indicator. 17. The method of claim 16
The control unit controls the transceiver to transmit, to the terminal, a message for adding the cell of the second base station as a secondary cell group for the terminal based on the measurement result. A first base station that does. 17. The method of claim 16,
The first radio access technology is long term evolution (LTE), and the second radio access technology is new radio (NR),
According to dual connectivity, the first base station operates as a master node (MN) for the terminal, and the second base station operates as a secondary node (SN) for the terminal. base station.

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